| Message ID | 1392497585-5084-4-git-send-email-sakari.ailus@iki.fi (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Sakari, Some minor comments: On 02/15/2014 09:53 PM, Sakari Ailus wrote: > Some devices do not produce timestamps that correspond to the end of the > frame. The user space should be informed on the matter. This patch achieves > that by adding buffer flags (and a mask) for timestamp sources since more > possible timestamping points are expected than just two. > > A three-bit mask is defined (V4L2_BUF_FLAG_TSTAMP_SRC_MASK) and two of the > eight possible values is are defined V4L2_BUF_FLAG_TSTAMP_SRC_EOF for end of > frame (value zero) V4L2_BUF_FLAG_TSTAMP_SRC_SOE for start of exposure (next > value). > > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> > --- > Documentation/DocBook/media/v4l/io.xml | 31 ++++++++++++++++++++++++------ > drivers/media/v4l2-core/videobuf2-core.c | 4 +++- > include/media/videobuf2-core.h | 2 ++ > include/uapi/linux/videodev2.h | 4 ++++ > 4 files changed, 34 insertions(+), 7 deletions(-) > > diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml > index 46d24b3..fbd0c6e 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -653,12 +653,6 @@ plane, are stored in struct <structname>v4l2_plane</structname> instead. > In that case, struct <structname>v4l2_buffer</structname> contains an array of > plane structures.</para> > > - <para>For timestamp types that are sampled from the system clock > -(V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC) it is guaranteed that the timestamp is > -taken after the complete frame has been received (or transmitted in > -case of video output devices). For other kinds of > -timestamps this may vary depending on the driver.</para> > - > <table frame="none" pgwide="1" id="v4l2-buffer"> > <title>struct <structname>v4l2_buffer</structname></title> > <tgroup cols="4"> > @@ -1119,6 +1113,31 @@ in which case caches have not been used.</entry> > <entry>The CAPTURE buffer timestamp has been taken from the > corresponding OUTPUT buffer. This flag applies only to mem2mem devices.</entry> > </row> > + <row> > + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant></entry> > + <entry>0x00070000</entry> > + <entry>Mask for timestamp sources below. The timestamp source > + defines the point of time the timestamp is taken in relation to > + the frame. Logical and operation between the > + <structfield>flags</structfield> field and > + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> produces the > + value of the timestamp source.</entry> > + </row> > + <row> > + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_EOF</constant></entry> > + <entry>0x00000000</entry> > + <entry>"End of frame." The buffer timestamp has been taken More a typographical thing than anything else: I prefer this: "End Of Frame": the buffer... The capitalization links back to the EOF abbreviation more directly. > + when the last pixel of the frame has been received or the I would say: "after the last pixel of the frame has been received or after the" The "when" word suggests that it is exactly "when", which is not true in practice. > + last pixel of the frame has been transmitted.</entry> > + </row> > + <row> > + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_SOE</constant></entry> > + <entry>0x00010000</entry> > + <entry>"Start of exposure." The buffer timestamp has been taken Start Of Exposure: the buffer... > + when the exposure of the frame has begun. This is only Should 'when' be replaced with 'after' here as well? I think Laurent has to decide that. Regards, Hans > + valid for buffer type > + <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>.</entry> > + </row> > </tbody> > </tgroup> > </table> > diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c > index 5a5fb7f..6e314b0 100644 > --- a/drivers/media/v4l2-core/videobuf2-core.c > +++ b/drivers/media/v4l2-core/videobuf2-core.c > @@ -2195,7 +2195,9 @@ int vb2_queue_init(struct vb2_queue *q) > WARN_ON(!q->io_modes) || > WARN_ON(!q->ops->queue_setup) || > WARN_ON(!q->ops->buf_queue) || > - WARN_ON(q->timestamp_type & ~V4L2_BUF_FLAG_TIMESTAMP_MASK)) > + WARN_ON(q->timestamp_type & > + ~(V4L2_BUF_FLAG_TIMESTAMP_MASK | > + V4L2_BUF_FLAG_TSTAMP_SRC_MASK))) > return -EINVAL; > > /* Warn that the driver should choose an appropriate timestamp type */ > diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h > index bef53ce..b6b992d 100644 > --- a/include/media/videobuf2-core.h > +++ b/include/media/videobuf2-core.h > @@ -312,6 +312,8 @@ struct v4l2_fh; > * @buf_struct_size: size of the driver-specific buffer structure; > * "0" indicates the driver doesn't want to use a custom buffer > * structure type, so sizeof(struct vb2_buffer) will is used > + * @timestamp_type: Timestamp flags; V4L2_BUF_FLAGS_TIMESTAMP_* and > + * V4L2_BUF_FLAGS_TSTAMP_SRC_* > * @gfp_flags: additional gfp flags used when allocating the buffers. > * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32 > * to force the buffer allocation to a specific memory zone. > diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h > index e9ee444..82e8661 100644 > --- a/include/uapi/linux/videodev2.h > +++ b/include/uapi/linux/videodev2.h > @@ -695,6 +695,10 @@ struct v4l2_buffer { > #define V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN 0x00000000 > #define V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC 0x00002000 > #define V4L2_BUF_FLAG_TIMESTAMP_COPY 0x00004000 > +/* Timestamp sources. */ > +#define V4L2_BUF_FLAG_TSTAMP_SRC_MASK 0x00070000 > +#define V4L2_BUF_FLAG_TSTAMP_SRC_EOF 0x00000000 > +#define V4L2_BUF_FLAG_TSTAMP_SRC_SOE 0x00010000 > > /** > * struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor > -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi Hans, Thanks for your comments. On Mon, Feb 17, 2014 at 09:54:53AM +0100, Hans Verkuil wrote: ... > > @@ -1119,6 +1113,31 @@ in which case caches have not been used.</entry> > > <entry>The CAPTURE buffer timestamp has been taken from the > > corresponding OUTPUT buffer. This flag applies only to mem2mem devices.</entry> > > </row> > > + <row> > > + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant></entry> > > + <entry>0x00070000</entry> > > + <entry>Mask for timestamp sources below. The timestamp source > > + defines the point of time the timestamp is taken in relation to > > + the frame. Logical and operation between the > > + <structfield>flags</structfield> field and > > + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> produces the > > + value of the timestamp source.</entry> > > + </row> > > + <row> > > + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_EOF</constant></entry> > > + <entry>0x00000000</entry> > > + <entry>"End of frame." The buffer timestamp has been taken > > More a typographical thing than anything else: I prefer this: > > "End Of Frame": the buffer... > > The capitalization links back to the EOF abbreviation more directly. Fixed, same for the similar one below. > > + when the last pixel of the frame has been received or the > > I would say: "after the last pixel of the frame has been received or after the" > > The "when" word suggests that it is exactly "when", which is not true in > practice. That's the intent nonetheless: to take the timestamp at the end of the frame, not an unspecified time after the event has taken place. I'd rather add a note that there's a level of impreciseness in taking the timestamp, such as: "In practice, software generated timestamp will typically be read from the clock a small amount of time after the last pixel has been received, depending on the system and other activity in it." That would probably be best put somewhere else in the document, though.
Hi Sakari, > From: Sakari Ailus [mailto:sakari.ailus@iki.fi] > Sent: Saturday, February 15, 2014 9:53 PM > > Some devices do not produce timestamps that correspond to the end of > the frame. The user space should be informed on the matter. This patch > achieves that by adding buffer flags (and a mask) for timestamp sources > since more possible timestamping points are expected than just two. > > A three-bit mask is defined (V4L2_BUF_FLAG_TSTAMP_SRC_MASK) and two of > the eight possible values is are defined V4L2_BUF_FLAG_TSTAMP_SRC_EOF > for end of frame (value zero) V4L2_BUF_FLAG_TSTAMP_SRC_SOE for start of > exposure (next value). > Changes in videobuf2-core.c look good. > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> Acked-by: Kamil Debski <k.debski@samsung.com> > --- > Documentation/DocBook/media/v4l/io.xml | 31 > ++++++++++++++++++++++++------ > drivers/media/v4l2-core/videobuf2-core.c | 4 +++- > include/media/videobuf2-core.h | 2 ++ > include/uapi/linux/videodev2.h | 4 ++++ > 4 files changed, 34 insertions(+), 7 deletions(-) > > diff --git a/Documentation/DocBook/media/v4l/io.xml > b/Documentation/DocBook/media/v4l/io.xml > index 46d24b3..fbd0c6e 100644 > --- a/Documentation/DocBook/media/v4l/io.xml > +++ b/Documentation/DocBook/media/v4l/io.xml > @@ -653,12 +653,6 @@ plane, are stored in struct > <structname>v4l2_plane</structname> instead. > In that case, struct <structname>v4l2_buffer</structname> contains an > array of plane structures.</para> > > - <para>For timestamp types that are sampled from the system clock > -(V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC) it is guaranteed that the > timestamp is -taken after the complete frame has been received (or > transmitted in -case of video output devices). For other kinds of - > timestamps this may vary depending on the driver.</para> > - > <table frame="none" pgwide="1" id="v4l2-buffer"> > <title>struct <structname>v4l2_buffer</structname></title> > <tgroup cols="4"> > @@ -1119,6 +1113,31 @@ in which case caches have not been used.</entry> > <entry>The CAPTURE buffer timestamp has been taken from the > corresponding OUTPUT buffer. This flag applies only to > mem2mem devices.</entry> > </row> > + <row> > + > <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant></entry> > + <entry>0x00070000</entry> > + <entry>Mask for timestamp sources below. The timestamp source > + defines the point of time the timestamp is taken in relation > to > + the frame. Logical and operation between the > + <structfield>flags</structfield> field and > + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> produces > the > + value of the timestamp source.</entry> > + </row> > + <row> > + > <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_EOF</constant></entry> > + <entry>0x00000000</entry> > + <entry>"End of frame." The buffer timestamp has been taken > + when the last pixel of the frame has been received or the > + last pixel of the frame has been transmitted.</entry> > + </row> > + <row> > + > <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_SOE</constant></entry> > + <entry>0x00010000</entry> > + <entry>"Start of exposure." The buffer timestamp has been > taken > + when the exposure of the frame has begun. This is only > + valid for buffer type > + <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>.</entry> > + </row> > </tbody> > </tgroup> > </table> > diff --git a/drivers/media/v4l2-core/videobuf2-core.c > b/drivers/media/v4l2-core/videobuf2-core.c > index 5a5fb7f..6e314b0 100644 > --- a/drivers/media/v4l2-core/videobuf2-core.c > +++ b/drivers/media/v4l2-core/videobuf2-core.c > @@ -2195,7 +2195,9 @@ int vb2_queue_init(struct vb2_queue *q) > WARN_ON(!q->io_modes) || > WARN_ON(!q->ops->queue_setup) || > WARN_ON(!q->ops->buf_queue) || > - WARN_ON(q->timestamp_type & ~V4L2_BUF_FLAG_TIMESTAMP_MASK)) > + WARN_ON(q->timestamp_type & > + ~(V4L2_BUF_FLAG_TIMESTAMP_MASK | > + V4L2_BUF_FLAG_TSTAMP_SRC_MASK))) > return -EINVAL; Looks good. > > /* Warn that the driver should choose an appropriate timestamp > type */ diff --git a/include/media/videobuf2-core.h > b/include/media/videobuf2-core.h index bef53ce..b6b992d 100644 > --- a/include/media/videobuf2-core.h > +++ b/include/media/videobuf2-core.h > @@ -312,6 +312,8 @@ struct v4l2_fh; > * @buf_struct_size: size of the driver-specific buffer structure; > * "0" indicates the driver doesn't want to use a custom > buffer > * structure type, so sizeof(struct vb2_buffer) will is used > + * @timestamp_type: Timestamp flags; V4L2_BUF_FLAGS_TIMESTAMP_* and > + * V4L2_BUF_FLAGS_TSTAMP_SRC_* > * @gfp_flags: additional gfp flags used when allocating the > buffers. > * Typically this is 0, but it may be e.g. GFP_DMA or > __GFP_DMA32 > * to force the buffer allocation to a specific memory zone. > diff --git a/include/uapi/linux/videodev2.h > b/include/uapi/linux/videodev2.h index e9ee444..82e8661 100644 > --- a/include/uapi/linux/videodev2.h > +++ b/include/uapi/linux/videodev2.h > @@ -695,6 +695,10 @@ struct v4l2_buffer { > #define V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN 0x00000000 > #define V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC 0x00002000 > #define V4L2_BUF_FLAG_TIMESTAMP_COPY 0x00004000 > +/* Timestamp sources. */ > +#define V4L2_BUF_FLAG_TSTAMP_SRC_MASK 0x00070000 > +#define V4L2_BUF_FLAG_TSTAMP_SRC_EOF 0x00000000 > +#define V4L2_BUF_FLAG_TSTAMP_SRC_SOE 0x00010000 > > /** > * struct v4l2_exportbuffer - export of video buffer as DMABUF file > descriptor > -- > 1.7.10.4 Best wishes,
On Tue, Feb 25, 2014 at 02:09:41PM +0100, Kamil Debski wrote: > Hi Sakari, > > > From: Sakari Ailus [mailto:sakari.ailus@iki.fi] > > Sent: Saturday, February 15, 2014 9:53 PM > > > > Some devices do not produce timestamps that correspond to the end of > > the frame. The user space should be informed on the matter. This patch > > achieves that by adding buffer flags (and a mask) for timestamp sources > > since more possible timestamping points are expected than just two. > > > > A three-bit mask is defined (V4L2_BUF_FLAG_TSTAMP_SRC_MASK) and two of > > the eight possible values is are defined V4L2_BUF_FLAG_TSTAMP_SRC_EOF > > for end of frame (value zero) V4L2_BUF_FLAG_TSTAMP_SRC_SOE for start of > > exposure (next value). > > > > Changes in videobuf2-core.c look good. > > > Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> > > Acked-by: Kamil Debski <k.debski@samsung.com> Many thanks for the reviews, Kamil! :-)
diff --git a/Documentation/DocBook/media/v4l/io.xml b/Documentation/DocBook/media/v4l/io.xml index 46d24b3..fbd0c6e 100644 --- a/Documentation/DocBook/media/v4l/io.xml +++ b/Documentation/DocBook/media/v4l/io.xml @@ -653,12 +653,6 @@ plane, are stored in struct <structname>v4l2_plane</structname> instead. In that case, struct <structname>v4l2_buffer</structname> contains an array of plane structures.</para> - <para>For timestamp types that are sampled from the system clock -(V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC) it is guaranteed that the timestamp is -taken after the complete frame has been received (or transmitted in -case of video output devices). For other kinds of -timestamps this may vary depending on the driver.</para> - <table frame="none" pgwide="1" id="v4l2-buffer"> <title>struct <structname>v4l2_buffer</structname></title> <tgroup cols="4"> @@ -1119,6 +1113,31 @@ in which case caches have not been used.</entry> <entry>The CAPTURE buffer timestamp has been taken from the corresponding OUTPUT buffer. This flag applies only to mem2mem devices.</entry> </row> + <row> + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant></entry> + <entry>0x00070000</entry> + <entry>Mask for timestamp sources below. The timestamp source + defines the point of time the timestamp is taken in relation to + the frame. Logical and operation between the + <structfield>flags</structfield> field and + <constant>V4L2_BUF_FLAG_TSTAMP_SRC_MASK</constant> produces the + value of the timestamp source.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_EOF</constant></entry> + <entry>0x00000000</entry> + <entry>"End of frame." The buffer timestamp has been taken + when the last pixel of the frame has been received or the + last pixel of the frame has been transmitted.</entry> + </row> + <row> + <entry><constant>V4L2_BUF_FLAG_TSTAMP_SRC_SOE</constant></entry> + <entry>0x00010000</entry> + <entry>"Start of exposure." The buffer timestamp has been taken + when the exposure of the frame has begun. This is only + valid for buffer type + <constant>V4L2_BUF_TYPE_VIDEO_CAPTURE</constant>.</entry> + </row> </tbody> </tgroup> </table> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c index 5a5fb7f..6e314b0 100644 --- a/drivers/media/v4l2-core/videobuf2-core.c +++ b/drivers/media/v4l2-core/videobuf2-core.c @@ -2195,7 +2195,9 @@ int vb2_queue_init(struct vb2_queue *q) WARN_ON(!q->io_modes) || WARN_ON(!q->ops->queue_setup) || WARN_ON(!q->ops->buf_queue) || - WARN_ON(q->timestamp_type & ~V4L2_BUF_FLAG_TIMESTAMP_MASK)) + WARN_ON(q->timestamp_type & + ~(V4L2_BUF_FLAG_TIMESTAMP_MASK | + V4L2_BUF_FLAG_TSTAMP_SRC_MASK))) return -EINVAL; /* Warn that the driver should choose an appropriate timestamp type */ diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h index bef53ce..b6b992d 100644 --- a/include/media/videobuf2-core.h +++ b/include/media/videobuf2-core.h @@ -312,6 +312,8 @@ struct v4l2_fh; * @buf_struct_size: size of the driver-specific buffer structure; * "0" indicates the driver doesn't want to use a custom buffer * structure type, so sizeof(struct vb2_buffer) will is used + * @timestamp_type: Timestamp flags; V4L2_BUF_FLAGS_TIMESTAMP_* and + * V4L2_BUF_FLAGS_TSTAMP_SRC_* * @gfp_flags: additional gfp flags used when allocating the buffers. * Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32 * to force the buffer allocation to a specific memory zone. diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h index e9ee444..82e8661 100644 --- a/include/uapi/linux/videodev2.h +++ b/include/uapi/linux/videodev2.h @@ -695,6 +695,10 @@ struct v4l2_buffer { #define V4L2_BUF_FLAG_TIMESTAMP_UNKNOWN 0x00000000 #define V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC 0x00002000 #define V4L2_BUF_FLAG_TIMESTAMP_COPY 0x00004000 +/* Timestamp sources. */ +#define V4L2_BUF_FLAG_TSTAMP_SRC_MASK 0x00070000 +#define V4L2_BUF_FLAG_TSTAMP_SRC_EOF 0x00000000 +#define V4L2_BUF_FLAG_TSTAMP_SRC_SOE 0x00010000 /** * struct v4l2_exportbuffer - export of video buffer as DMABUF file descriptor
Some devices do not produce timestamps that correspond to the end of the frame. The user space should be informed on the matter. This patch achieves that by adding buffer flags (and a mask) for timestamp sources since more possible timestamping points are expected than just two. A three-bit mask is defined (V4L2_BUF_FLAG_TSTAMP_SRC_MASK) and two of the eight possible values is are defined V4L2_BUF_FLAG_TSTAMP_SRC_EOF for end of frame (value zero) V4L2_BUF_FLAG_TSTAMP_SRC_SOE for start of exposure (next value). Signed-off-by: Sakari Ailus <sakari.ailus@iki.fi> --- Documentation/DocBook/media/v4l/io.xml | 31 ++++++++++++++++++++++++------ drivers/media/v4l2-core/videobuf2-core.c | 4 +++- include/media/videobuf2-core.h | 2 ++ include/uapi/linux/videodev2.h | 4 ++++ 4 files changed, 34 insertions(+), 7 deletions(-)